The broad, long-term objectives of this application are to better understand the effects of aging on pilots' safety performance and to improve aviation safety. The specific aims are: (1) to determine age-related variations in the relative risk of crash involvement for commercial aviation pilots; (2) to examine age-related variations in pilot errors in airline and commuter/air taxi crashes; and (3) to disseminate the study results in scientific and public communities and make relevant policy recommendations. Federal Aviation Regulations mandate retirement at age 60 years for all major airline (Part 121) pilots. This policy (usually known as the "age-60 rule") has been the subject of continuing controversy and research since its establishment in 1960. Previous studies examining the effects of aging on piloting performance were conducted primarily under controlled experimental conditions using flight simulators. Few observational studies have examined the association of pilot age with the risk of crash involvement. With funding from the National Institute on Aging, the investigators followed a birth cohort of 3,306 commuter/air taxi (Part 135) pilots from 1987 to 1997 and found that crash risk remained fairly stable as the pilots aged from their late 40s to late 50s. There were insufficient data from the longitudinal study to assess the crash risk beyond age 60. In the proposed project, the investigators will use the case-control design and surveillance data to assess age-related variations in the relative risk of crash involvement for both Part 121 and Part 135 pilots. Cases are pilots who were involved in major airline crashes (Part 121 cases, n=550) or in commuter/air taxi crashes (Part 135 cases, n=2,700) during 1983 through 2005, identified from the National Transportation Safety Board's aviation crash data system. Controls (1,100 Part 121 pilots and 2,700 Part 135 pilots) will be matched with cases on important confounding variables and selected at random from the Federal Aviation Administration's incident data system. Quantitative and textual data for each of the 550 major airline crashes and 2,700 commuter air taxi crashes will be analyzed in depth to delineate age-related differences in pilot error and other contributing factors. Results of this project can provide valuable empirical data for understanding the relationship between pilot aging and safety performance and for reassessing the "age-60 rule."